It would have been easy to predict the same five teams as last year to make this year’s National League playoffs. After all, only six teams finished above .500, and none of the under-.500 teams made obvious improvements. But we know the same teams never make the playoffs. What usually happens is at least one playoff team stumbles out of the gate and never recovers. That’s happened this season to the San Francisco Giants, Los Angeles Dodgers and New York Mets, all sitting under .500. What’s gone wrong?

Here’s the dirty little secret about the Giants: The Madison Bumgarner-Matt Cain-Tim Lincecum era actually only existed for two seasons. That trio led the Giants to the World Series title in 2010 and pitched well in 2011, when the club missed the playoffs, the year Buster Posey got injured. In 2012, they won another championship, although Lincecum posted a 5.18 ERA and was banished to the bullpen in the World Series.

Since then, however, the Giants have been a good team but not a great one, with the 2014 playoff run that culminated in a third title in five seasons masking the fact that this team has failed to win 90 games since 2012. Look at the past four seasons:

• 2013: 76-86. Bumgarner was good, but Cain (0.5 WAR) and Lincecum (minus-0.6) weren’t, and Barry Zito and Ryan Vogelsong were even worse.

• 2014: 88-74. Made the playoffs as a wild card, with help from a terrible NL West that featured the 96-loss Rockies and 98-loss Diamondbacks. Cain got injured and Lincecum once again had negative WAR and appeared in one game in relief the entire postseason. Bumgarner’s historic playoff run carried the team to the title.

• 2015: 84-78. They tried to milk another year out of Cain and Lincecum (plus Tim Hudson and Jake Peavy), but it didn’t work, as Cain and Lincecum combined to make just 26 starts.

• 2016: 87-75. In a watered-down National League, once again made the playoffs as a wild card. The Giants finally acknowledged their rotation problems by signing Johnny Cueto and Jeff Samardzija, but Cain and Peavy were terrible (combined 5.58 ERA over 38 starts).

Obviously, most franchises would love those results. My point is that the Giants have had weaknesses and didn’t enter 2017 with a lot of margin for error. Coming off an 87-win season, the only significant improvement they made was signing closer Mark Melancon. They had no prospects projected to make a major impact; they ignored an outfield that had clear issues in center field -- where they were going to rely on a 33-year-old Denard Span coming off a subpar 1.0-WAR season -- and in left field, where they didn’t re-sign Angel Pagan and were going to attempt a tag-team approach with Jarrett Parker ... or Mac Williamson ... or, well, the Giants have already started six different players there.

The two positions have been a disaster. Entering Thursday, the Giants’ left fielders are hitting .113/.191/.175. The center fielders are hitting .170/.247/.227. They resorted to trying infield reserve Aaron Hill out there and have had so many injuries that they dug up Drew Stubbs and Michael Morse from the remainder bin at Marshall’s. (OK, Morse hit a dramatic, pinch-hit home run Wednesday to tie a game the Giants won over the Dodgers in 10 innings.)

Those guys aren’t solutions, and while the outfield won’t be this bad all season, it’s still going to be one of the worst groups in the majors. That’s why some analysts felt the money spent on Melancon would have been better spent on a left fielder or center fielder (Dexter Fowler would have been a nice fit). Then you throw in Bumgarner’s injury. Over the past three seasons, the Giants are 59-40 in games Bumgarner starts. If he’s out the estimated two months, maybe he misses 12 starts. The Giants could be expected to go 7-5 in those games; maybe now they go 5-7 or 4-8.

So that injury alone is just a little bump in the road, but all this comes on top of the 8-15 start. That start is in the books, and the result is that no team has suffered a bigger decline in their projected record so far than the Giants, according to Jeff Sullivan at FanGraphs; San Francisco's projected record has gone from 88.5 wins to 80.1. Put it this way. If you thought the Giants were a 90-win team, they’ll have to go 82-57 the rest of the way, a .590 winning percentage (a 96-win pace). That’s not unattainable; but do the Giants have that level of talent?

There’s even the possibility the Giants could turn into the 2012 Phillies. Remember, those Phillies were better than the Giants: 92 wins and a World Series title in 2008, 93 wins and a World Series appearance in 2009, 97 wins in 2010 and 102 wins in 2011. They dropped to .500 in 2012 and then collapsed after that. The Giants’ lineup now isn’t as old as the Phillies’ lineup was then (every regular except Hunter Pence was older than 30 on that team), but Brandon Belt and Joe Panik are the only Giants regulars younger than their age-30 seasons. The Phillies were eventually struck down by injuries to Roy Halladay and then Cliff Lee the following season, but the Giants’ rotation is also precariously thin in depth. And remember, Cueto has an out clause after this season. The farm system hasn’t produced a quality starter since Bumgarner arrived in 2010.

With the Rockies and Diamondbacks off to good starts -- see Jerry Crasnick’s article -- the Giants have dug themselves a dangerous hole. They’re going to have to play better than they’ve played the past five years to get back to the postseason.

There’s less to worry about for the Giants’ rivals to the south, not that the Dodgers aren’t without their own problems. In fact, their issues start in the outfield as well. While the Giants are last in the majors in wOBA from their outfielders, the Dodgers aren’t much better at 26th (entering Thursday). When Cody Bellinger was called up and inserted into left field, he became the ninth different outfielder to start for the Dodgers. Remember a couple years ago when everyone was worried the Dodgers had too many outfielders? Not a problem in 2017.

The Dodgers didn’t want to call up Bellinger, even though he was hitting well at Triple-A, but Brett Eibner and Trayce Thompson aren’t good options, and Bellinger is probably a better player right now than Andrew Toles, even if he's barely played above Double-A and is going to strike out a lot. Bellinger is another left-handed batter as well, and -- small-sample-size alert! -- the Dodgers are once again struggling against lefties. Power has been a problem, as Adrian Gonzalez hasn't homered, Justin Turner hasn't homered and Joc Pederson (currently on the disabled list with a hamstring issue) hasn't homered since Opening Day. That puts pressure on Bellinger to help provide some pop behind Corey Seager.

The bigger concerns are probably with the starting rotation, where Rich Hill can’t stay off the DL with his blister problems, Kenta Maeda has allowed seven home runs in 19 innings and Hyun-Jin Ryu has allowed six homers in 21⅓ innings. They have a lot more depth here than the Giants, and Julio Urias finally made his first start Thursday, which is why their projected record hasn’t changed since the start of the season.

Then we get to the Mets. Thursday was as bad a day as a team can have. First, Noah Syndergaard missed his scheduled outing with biceps discomfort. Matt Harvey replaced him and wasn’t good, and after the game it was revealed that Harvey had worked hard Wednesday and didn’t know he was going to start until three hours before game time. Then Yoenis Cespedes left the game after pulling up lame on a double, reinjuring the hamstring that had caused him to miss a few games ... except this looked even worse, as he needed help leaving the field.

Hey, at least Jose Reyes got his first RBI!

The Braves ended up winning 7-5, the Mets fell to 4-10 at home, and New York has lost 10 of 11. They’re hitting .209 -- only the Royals are worse -- and rank 27th in wOBA, with only the Giants, Blue Jays and Royals below them. They’ve scored 33 runs during this 11-game stretch.

So, yeah, the offense. The starting pitching, however, hasn’t dominated like it needs to, ranking 19th in the majors in ERA. Their peripherals are much better -- the Mets rank sixth in strikeout rate, second in lowest walk rate, eighth in home run rate -- but they rank last in left-on-base percentage. The starters have stranded just 65.5 percent of their runners, compared to the league average of 74 percent. Considering the other metrics are positive, they should improve in that area.

Still, like the Giants, the hole is getting deep. They’re already 7½ games behind the Nationals and their two best players might be heading to the disabled list. If you think they’re panicking in Queens, you’re right. Terry Collins had a testy postgame media session after Thursday's loss. "It's gotta start right now," he fumed. Indeed.